Four-sided bookshelf



FIG. 1 is an elevational view of one side of a four-sided bookshelfshowing my new design, the sides not shown being identical thereto;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof; and

FIG. 4 is a perspective view thereof.

The ornamental design for a four-sided bookshelf, as shown anddescribed.